Apparatus for manufacturing hollow articles



June 13, W67 E. R. ARLO APPARATUS FOR MANUFACTURING HOLLOW ARTICLES 4Sheds-Sheet 1 Original Filed Feb. 26, .1962

ATTORNEY June 13, 167 E. R; ARLO 3,324,5W7

, APPARATUS FOR MANUFACTURING HOLLOW ARTICLES Original Filed Feb. 26,1962 4 Sheets-Sheet P,

INVENTOR ATTORNEY June 113, 1967 E. R. ARLO 3,

APPARATUS FOR- MANUFACTURING HOLLOW ARTICLES Originai Filed Feb. 26,1962 4 Sheets-Sheet ATTORNEY June 13, 1967 E. R. ARLO APPARATUS FORMANUFACTURING HOLLOW ARTICLES 4 Sheets-Sheet 4 Original Filed Feb. 26,1962 IN VENTOR ATTORNEY 3,324,507 APPARATUS FOR MANUFACTURING HULLUWARTICLES Ebhe Rolf Arlp, Copenhagen, Denmark, assignor, by mesneassignments, to Esso Chemical Company Inc., New York, N.Y.

Original application Feb. 26, 1962, Ser. No. 197,807, new Patent No.3,265,788. Divided and this application Apr. l, 1966, Ser. No. 540,794

$ Claims. (Cl. 18-5) This application is a divisional application ofSer. No. 197,807, filed Feb. 26, 1962, now U. 3. Patent No. 3,265,- 788.

The invention relates to an apparatus for manufacturing hollow articlesin which plate or tubular material is rendered plastic by heating, andexpanded in a mold.

During late years apparatus has been used where plastic material hasbeen extruded in the shape of a hose, and the plastic material is in itsstill hot condition enclosed and blown up. After a certain time, whenthe plastic material has been stabilized, the mold is opened and thehollow body removed whereafter a fresh piece of hose is enclosed in themold and so on. However, a number of difiiculties have cropped up inthis known apparatus seeing that it is impossible to undertake anerTective adaptation of the plasticity of the material. For this reasonit has been necessary to give up the manufacturing of certain articlesfrom certain materials, especially polyvinylchloride, which mustotherwise be considered a very favorable material for many purposes,especially when it is a question of obtaining tightness againstpermeation of certain liquids. Moreover, it is not possible in thehitherto known methods in many cases to obtain an attractive finelyperformed smooth surface, just as the known method can hardly givebottles of a clear transparent material.

In the known apparatus, the extruding takes place by means of anextruder having a horizontal extruder tube on which is arranged an anglehead which, however, has an inclination to give an irregular wry hose.Wryness may also easily appear from air currents for the ventilation ofthe room in question. Finally, the extruding will cause that dust fromthe plastic raw material is spread in the room, and this may deposititself on the pressed out hose.

It is the object of the invention to provide an improved apparatus inwhich the said drawbacks are fully or partly remedied. Thecharacteristic feature of the invention is that the thermoplasticmaterial is carried to the molding machine by means of a feedingmechanism which is synchronized with means for opening and closing themold. In this manner, a very quick manufacture can be obtained.Moreover, it is possible to get a better product than by the knownapparatus seeing that it is easy to get articles which are especiallywell suited for the heating and molding operation, e.g. calibrated hosepieces with an especially smooth outer side. On the whole, advantageswill be obtained in many respects which will be easily realized by anexpert.

As work pieces, it is advantageous to use tubular pieces which arearranged in individual holders in the transport mechanism. Such hosepieces can fairly easily be made with an exactly desired weight andthickness of goods thus obtaining a uniform product in the blowingmolding.

3324,57 Patented June 13, 1967 As start material, it is advantageous touse tubular plastic material which is fiat and has such properties thatwhen heated it will assume a shape having substantially a circular crosssection. Such flat tubular material is convenient for storing andtransport. It is, moreover, easy to make, e.g. in the manner that hosematerial is extruded having a round cross section, and this hosematerial is flattened when it has such a temperature as will give riseto latent tensions in the material when same is flattened.Advantageously, the material may be used directly from a flat coiled-upcondition. Thus, the material is particularly easy to store andtransport. The material may with advantage be somewhat heated before theuncoiling. Such heating is of special importance in case of relativelystiff material such as polyvinylchloride. Another form of material usedincludes a tubular flat portion which is bent with equally big intervalsand lternatively to opposite sides to form equally long distances lyingclosely against each other. At the bends there may be incisions so thatthe pieces are only connected with each other by narrow connecting partswhich are easly to break, possibly in cold condition.

The mold may with advantage be moved between two positions where in oneposition it is closed round a work piece fed by the transport mechanismwhereafter it is in closed condition moved to the other position whereit does not constitute any hindrance for the feeding of the next workpiece. Thus, the transport mechanism may be constructed in a rathersimple manner, e.g. with a horizontal feeding path for the work pieces.

The heating of the work pieces may advantageously take place by means ofhot air. Thus, an even heating of the work pieces may be obtained, ifdesired, also in the interior of the tubular work pieces. The workpieces may advantageously be transported in vertical position held firmby holding members at the top. In this manner the work piece may beheated rather strongly without being deformed during the plastificationin an unfortunate manner or without adhering to machine parts in adetrimental way. Work pieces having a through opening may with advantagebe transported through a room having vertical currents of hot air. Inthis manner, part of the hot air will pass in through the work piecesthus heating the latter from the inside.

The invention furthermore relates to a machine that has a divided mold,means for the opening and closing of the mold, a transport mechanism forthe transport of plastic work pieces through a heating apparatus, meansfor conveying the work pieces one at a time in between the mold parts,and means for blowing up a work piece placed in the closed mold. Bymeans of such a machine, a quick and satisfactory production can beobtained. The transport mechanism may with advantage have an endlessconveyor band with holders for the work pieces. In this manner, a simpleand favorable machine is obtained. In order to get a sufficiently longheating period, it is possible to let the conveyor band move along somecurved path, egg. in waves to and fro or up and down or helicallydownwards. The mold may advantageously be arranged movably between twopositions by means of a driving mechanism where in one position in opencondition it encloses a work piece and is closed round the sameWhereafter it is moved to the other position where it does notconstitute any hinderance for the feeding of the next work piece. Inthis manner, an especially practical construction is obtained asexplained above. The m-old may be movable in the vertical direction.This direction of movement has proved particularly advantageous. Themold may, however, instead be moved in another manner, e.g. by beingswung about a horizontal or vertical axis. The transport mechanism maywith advantage extend through a room through which a current of hot airis blown. In this manner, a favorable even heating of the work piecesmay be obtained. The air current may advantageously be vertical. Thus,the heat can be distributed evenly in the whole length of verticallysuspended work pieces. The transport mechanism may advantageously bearranged for the feeding of the work pieces in steps and for retainingeach work piece for a short time at the place where the mold is broughtto close round a work piece. In this manner, certainty can be obtainedfor having the work pieces in the correct position when the mold isclosed.

The transport mechanism may with advantage have an endless path forseparate conveyor elements the relative distance of which on the pathcan be varied and which have each at least one holder for a work piece.The conveyor elements may advantageously at least in a heating sector,be fed close to each other, while they are individually transferred fromthe heating sector to the place, where the mold closes, by means of acomparatively long movement in steps in the path. In this manner, thework pieces will stick fairly close together during the transportthrough the heating sector in which manner it is obtained that thelatter can be constructed with comparatively small dimensions. Therelatively long movement in steps insures that the nearest followingwork piece is at a safe distance behind during the closing of the mold.

The plastic material may advantageously be fed continuously through aheating apparatus, e.g. in case of a continuous band of plasticmaterial. In this manner, it is in many cases possible to obtain a quickworking and a uniform quality.

The plastic material may be subjected to a heating varying in thelongitudinal direction. Thus, it will be possible to give the part whichis to form the bottom of a bottle, and which is to be welded, anespecially strong heating, whereas the remaining part of the length isheated less in which manner favorable molding and welding conditions areobtained. It will also be possible to vary the heating according to thecircumferential direction, e.g. in the way that a certain zone is heatedparticularly strongly, e.g. in case this zone is to have a text printedon it or an object welded to it.

The plastic material may advantageously be fed with varying speed, e.g.in case of a continuous plastic band. Thus, it is possible in certaininstances to obtain a suitable heating of different parts of the plasticmaterial. Moreover, the movements may in this manner he made easier. Theplastic band material may, moreover, advantageously be fed in steps, thelength of the steps corresponding to the piece to be insertedinto themold. This will in many cases be the most advantageous carrying out ofthe method seeing that in this case it is obtained that it isunnecessary to move the mold as a whole which would otherwise normallybe necessary. Moreover, the heating may in this manner be carriedthrough in a particularly favorable way.

The plastic band material may be carried from an extruder to a heatingapparatus. Thus, an even and quick manufacture is obtained. The plasticband material may after the extruding pass through a cooling andcalibrating appartus. Thus, a material is obtained having a much moreuniform character than by the usual direct feeding from extruder tomold. The plastic band material may be carried from an extruder having ahorizontal direction of pressing out past guiding members to the inletopening arranged at the top of a heating apparatus with a vertical pathfor the plastic material. In such an extruder with a horizontal pressingout direction it is possible to support the pressed out bandeffectively, and it is, therefore, permissible to allow the band to bepressed out with high temperature and a correspondingly considerableplasticity whereafter the band is cooled off on its path to the heatingapparatus, e.g. by means of a calibrating apparatus in which manner amaterial is obtained having the uniform good quality required fromextruded hoses, e.g. garden watering hoses. It is not necessary for thehose to be cooled to room temperature before the heating apparatus. Onthe contrary, it will, as a rule, be advantageous that it is only cooledto such an extent that it is stable and can stand the passage to theheating apparatus so that its interior has a rather considerabletemperature.

To the heating apparatus may be fed stored plastic band material. Thishas in many cases very considerable advantages seeing that it will beeasy to change between several qualities and colors. When carrying outthe invention in this way it will furthermore be particularly convenientto produce comparatively small production runs which are very costly andunpractical in the hitherto known methods seeing that the adjustment andadaptation work in connection with the same is very great.

The drawing shows schematically three embodiments of a machine accordingto the invention, in which:

FIG. 1 shows a machine according to one embodiment in front view andwith certain parts removed for the sake of clearness;

FIG. 2 is a perspective illustration of parts of a machine according toanother embodiment;

FIG. 3 is a top view of parts of the machine;

FIG. 4 is a section according to the line IV-IV in FIG. 3;

FIG. 5 is a section of the transport path with conveyor elements in themachine;

FIG. 6 is a top view of a conveyor element; and

FIG. 7 is a schematic side view of a machine of a third embodiment.

The machine shown in FIG. 1 employs a known bottle blowing apparatushaving a lower frame 1 with upwardly directed guiding columns 2 and 3for a table 4 which can be lowered and lifted by means of pressure meanscylin ders. On the table 4, two mold parts 5 and 6 are displaceablyarranged which can be moved horizontally towards and away from eachother by pressure means cylinders 7 and 8. Moreover, there is in thetable 4 between the mold parts a vertical blowing nozzle 9 which can bemoved up and down by means of pressure means cylinders (not shown).

Above the said bottle blowing apparatus, which preferably constitutes aseparate unit independent of the rest of the machine, there is atransport mechanism which to all essentials consists of an endless chainwhich by means of a chain wheel (not shown) is arranged with a verticalpath It), a horizontal path 11, horizontal to-and-fro extending paths12, 13, 14 and 15, an inclined path 16, an inclined path 17 and ahorizontal path 18 which is connected to the lowermost end of thevertical path 10. On the chain are interspaced holding members which mayconsist of a short conical pin and two or three catching members whichcan be brought to press inwardly against the conical pin. These holdingmembers are rotatably arranged on the chain links in such a manner thattheir axis of rotation is at right angles to the plane of the chain. Inconnection to the vertical path 10 there are guiding members, such as alink guide, cooperating with an arm on the rotatable holding members inwhich manner they are at least at the lower part of this path kept inposition with the axis for the conical pin extending out to one side. Atleast part of the chain 1048 is arranged in a box (not shown) throughwhich is admitted a vertical current of air, e.g. an upwardly directedcurrent of air. At the side of the path 10 there is a funnel 19 whichhas as shown two parallel sides and two other sides extending obliquelydownward towards each other toward a narrow bottom opening thelongitudinal edges of which are formed by the last mentioned sides. Thedistance between the two parallel sides is a little greater than thelength of the work pieces to be used so that such work pieces can ingreat numbers lie in the funnel with their longitudinal direction atright angles to the parallel sides. The bottom opening has such a sizethat one work piece at a time can pass down through the same. Beneaththe bottom opening there is a mechanism with means adapted to receivesuch a work piece and carry it. in its longitudinal direction towardsthe path It). A driving mechanism for these members and a drivingmechanism for the chain lit-13 are synchronized in such a manner thatthe transfer of a work piece to the path takes place when a set ofholding members is located at the place in question of the path 10. Theholding members may be guided in such a manner that the said catchingmembers are at this place moved away from the conical pin so that theend of a tubular work piece can be brought into engagement with this pinwhereafter the catching members are brought to press against the outerside of the work piece in towards the pin, e.g. by means of springmembers actuating the catching members. Thereafter the said transfermembers arranged beneath the funnel 19 are moved back to receive thenext work piece from the funnel and so on.

Gradually as the holding members of the chain are moved into the path11, the tubular plastic work pieces will on account of their weightswing down to vertical position as shown, and they will retain thisposition during the passage of the paths 12, 13, 14, 15 and 16. Thedriving mechanism of the chain may be so arranged that the movementtakes place in steps in such a manner that it is stopped whenever a workpiece has reached the lowermost position between the two inclined paths16 and 17. The movement of the bottle blowing apparatus is furthermoreadjusted to the movement of the chain 1948 in such a way that the moldis to all essentials at the same time as a work piece carried to theposition in question, brought into its upper position by a lifting ofthe table 4, and closed round the work piece by means of the pressuremeans cylinders 7 and 8. Immediately afterwards, air is blown through tonozzle 9 into the enclosed work piece so that the latter is brought intoabutment against the inner side of the mold. Thereafter, the table 4 islowered to such a position that there is room for the feeding of thenext work piece to the place in question between the inclined paths 1nand 17 of the chain. When the bottle in the mold is stabilized, the moldis opened, the bottle ejected, and the table 4 lifted to receive thenext work piece between the mold parts and so on. The movement of thechain 10418 is adjusted according to the time necessary for thestabilization so that this time, practically speaking, determines thespeed of production. By the passage through the said box or oven, thework pieces are heated by the vertical hot current of air. In order thatthe work pieces may also be heated from the inside, the conical pin ofthe holding members on the chain 10-18 may be hollow so that part of theair can pass up through the tubular work pieces and further on throughthe pin. Part of the heat may be transferred to the funnel 19 so thatthe work pieces are pre-heated. The chain 1 3 118 may, if desired, bedriven continuously at relatively slow speed. However, this requires anexact synchronization of the various movable parts since the mold has toclose around a work piece during the movement and the work pieces are tobe moved on to the holding members during the movement. The holdingmembers are preferably arranged in a replaceable manner so that it ispossible to mount holding members for work pieces with another diameterin the same way as the holding members may be arranged with greater orsmaller space between them on the chain. Accordingly,

the feeding speed of the chain must be variable. Moreover, thetemperature of the heating box must be able to be varied, or it may bedone in the Way that the work pieces are heated for a longer or shortertotal distance adjusted according to thickness and the necessarytemperature of the material in question. The heating box proper must beinsulated, and may include surrounding return channels having airheating means. The blowingup nozzle may be in its uppermost positionwhen the table is lifted and pulled down when the mold is opened andimmediately afterwards moved up again. It may, however, remain in itslower position during the lifting of the table and be moved quicklyupwards into the tubular work piece after the lifting of the table. Thiswill make the time especially short which must be allowed for theengagement of the blowing nozzle with the work piece. It is alsopossible to arrange the machine in such a manner that the mold is notmoved up and down, but the work pieces are moved in between the moldparts, e.g. by an inclined or vertical movement. Thus, the Work piecescan be carried from the chain to the mold by means of special holdingmembers carrying a work piece at the time away from the holding membersof the chain, e.g. in vertical direction in which manner the blowingnozzle may possibly cooperate by being moved up for engagement with thelower end of the Work piece and thereafter with the work piece down tothe mold.

It is also possible to have an embodiment where a conveyor band has anumber of mandrils serving as holding members for tubular work piecesand arranged to function as blowing nozzles, e.g. in the way that whenarriving at the mold they are put into connection with a compressed airpipe. Such mandrils may also be arranged upwardly directed or downwardlydirected on the active distance of the conveyor band. In case ofdownwardly directed blowing mandril, the removal of the bottles will,after the opening of the mold, be particularly convenient.

The transport mechanisms may be arranged in many other ways than the oneshown. The conveyor band may thus have vertical paths in lieu of theillustrated horizontal ones. The transport mechanism may also consist ofa rotatable round table. The work pieces may, if desired, be supportedat both ends during the transport, e.g. a mandril at one end andcatching members at the other end.

Instead of a heating box it is possible to use a channel enclosing thetraveling path of the work pieces. The holding members for the workpieces may be arranged for individual feeding in guiding members,especially by rollers guided in tracks, where the work pieces can be fedvery closely during the heating and individually moved to a position forenclosure between the mold parts. Where a chain is employed, it ispossible to have holding members on either side of the same, if desired,two or more sets of holding members on either side in which case theremust be a corresponding number of molds next to each other on the table4.

If desired, it will also be possible to transfer work pieces, one at atime, from a magazine to the mold, e.g. by means of a rotatable arm orthe like transfer mechanism where the magazine has no real transportmechanism but may e.g. consist of of a funnel as the illustrated funnel19. The magazine may in such a case be heated. The transfer mechanismmay also be arranged in such a way that it keeps each of the work piecesfor a time in a heating apparatus. In this way, it is possible, ifdesired, to heat different parts of the work piece differently.

It will also be possible for the blowing-up process to use heated airand possibly also to use a heated mold. In this case, it is possible touse completely cold or only comparatively slightly pre-heaterl workpieces so that in spite of a small thickness of goods they have aconsiderable stiffness when introduced into the mold,

If desired, the mold may be moved so that at least for part of the wayit follows a work piece in the transport mechanism. In this case, itwill not be necessary to undertake the feeding operation in steps. Sucha movement of the mold may be obtained by placing the mold on a tablewhich rotates, e.g. about a horizontal or vertical axis.

In lieu of extruding work pieces, it is possible to use injection moldedwork pieces or work pieces produced in another way.

Often it will be especially advantageou to use fiat tubular pieces asmaterial since this will give a convenient storing and transport. In themachine illustrated, it will, however, be advantageous that the tubularpieces have to all essentials a round cross section. However, this maybe obtained by using tubular pieces having latent interior tensions.When such tubular pieces are placed in the funnel 19 and heated in thesame they will straighten themselves out to a practically round crosssection.

Instead of using a funnel 19 and a transfer mechanism from the funnel tothe transport chain, an operator may manually fasten the tubular pieceson the transport chain thereby obtaining a more secure function of thechain. In this connection, it is possible with special advantage to usea transport mechanism where both ends of the tubular pieces arefastened, e.g. one end on a blowing mandril and the other end in thecatching members.

The machine illustrated in FIGS. 26 has a bottle blowing apparatus asthe one shown in FIG. 1, and the corresponding parts of the apparatusare indicated by the same reference numbers 1 to 9. The apparatus has,however, two molds arranged side by side and two associated blowingnozzles 9.

The machine is furthermore equipped with a heating and transportapparatus comprising a horizontal endless path formed by a rail 20 (FIG.and comprising two semi-circular arcs 21 and 22, and two straightconnecting paths 23 and 24. In the groove there are a number of conveyorelements 25 having rounded end parts 26 and 27 and a narrow centralportion 28. The lower side is formed with sliding ribs 29 and 3t)resting on the bottom of the rail 20. In the sides of the rounded endparts 26 and 27 there are partly projecting balls 31, 32, 33 and 34loaded by pressure springs 35. On the upper side of the conveyor elementis fastened a cross bar 36 which carries at either end a holdingmechanism (not shown) for one end of a downwardly projecting hose pieceof thermoplastic material. Each conveyor element has furthermore at thetop a carrier member (not shown) co-operating with a driving arm 37rotating with a constant speed of rotation and the vertical axis ofrotation coincides with the vertical line through the center of the railare 21. The said carrier member on the conveyor element and the arm mustbe arranged for release from each other when the conveyor element is inthe position in the middle of the rail arc 21, and there may be othermembers to insure that the conveyor element is retained precisely in thesaid position, e.g. a pin which can be brought into engagement with theside of the conveyor element. The sides of the rail have grooves 38 intowhich the balls 31-35 engage and are guided.

The rail arc 22 and the connecting paths 23 and 24 are enclosed in aflat casing 32 which by means of a vertical partition wall 40 is dividedinto an outer and inner section. The partition wall 40 has its upperedge slightly below the ceiling in the casing 39 and its lower edgeslightly above the bottom of the casing. In the inner section of thecasing there are heating elements 41 and a ventilator fan 42 driven byan electric mot-or 43. At the two places where the rail 20 extends outof the casing 39 there are tightening means, e.g. the so-called conveyorsluices. The casing 39 also includes an adjustable outlet opening 44arranged in such a manner that there will be a slight suction from thesaid sluices. The casing 29 has at the transition between the rail are21 and the connecting path 24 an incision 45 serving as loading stationfor the plastic work pieces.

When using the machine illustrated in FIGS. 2-6, there is at either endof each of the cross bars as suspended a piece of hose of thermo-plasticmaterial. This suspension may be undertaken manually or by a machineoperation, in both cases at the incision 45. There are conveyor elcmentsin such a number that they fill the whole rail 20 with the exception ofthe 90 of the rail are 21, viz. from the path 23 to the middle of theare 21. The arm 37 rotating with constant speed will by each rotationcarry a conveyor element from the end of the path 23 to the middle ofthe are 21 where the element will move all the other elements one stepforward on the rail. To obtain a reduced conveyor speed of the feedingtwo or several arms 37 may be used. The release of the arm 37 from theconveyor element may be effected in the way that the arm is at themiddle of the are 21 lifted free of the carrier member of the element.The arm may be kept in its lifted position while it passes the conveyorelements on the 90 of the arc 21 from the middle of the same and up tothe path 24.

The bottle blowing apparatus 1-9 is arranged in such a manner that theblowing nozzles 9 are located vertically under the holder members of thecross bar of a conveyor element which is in its central position on therail are 21. Immediately after the conveyor element has been brought tothis position, the blowing nozzles are inserted into the two hosepieces, and the molds are closed around the latter whereafter air isblown into the hose pieces, and the table 4 with the molds is lowered.While the thus molded bottles are cooled for stabilization, the nextconveyor element is moved to the middle of the are 21. The molds areopened, the bottles removed, and the table lifted for the purpose ofenclosing the next couple of hose pieces.

In FIG. 7, 51 is an extruder having a horizontal extruder arm 52extending from the extruder head 53 from which there is continuously andwith constant speed extruded a hose 54 of thermo-plastic syntheticmaterial, such as polyvinylchloride or polyethylene. The hose is passedthrough a cooling apparatus 55 arranged in the vicinity of the extruderhead 53, which cooling apparatus is preferably arranged as a calibratingapparatus as is the normal process for the production of garden hosesand similar articles. From the cooling apparatus 55 the hose 54 iscarried through guiding rollers 56 to a driving roller 57 and from thereobliquely upwards and past a guiding roller 58 and down between thelatter and a driving roller 59. From here the hose 54 is carriedvertically down through a heating apparatus 60 having a vertical throughchannel for the hose. Uniformly distributed round this channel theheating apparatus 69 may have heating lamps or the like radiationheating members, preferably with depth effect. Along the lower edge ofthe heating apparatus a knife is displaceably driven by a pressure meanscylinder 61. Beneath the heating apparatus is arranged as so far knownbottle blowing apparatus as the one shown in FIG. 1.

During the working of the machine shown in FIG. 7, hose 54 is asmentioned extruded continuously and at a constant speed, and from theheating apparatus is fed continuously and at constant speed such hosematerial as has been cooled and calibrated in the cooling apparatus 55so that it has a uniform character. The cooling and the distance betweenthe cooling apparatus 55 and the heating apparatus 60 may be arranged insuch a way that when it arrives at the heating apparatus the hose iscomparatively cold on the outside but has an elevated temperature in theinterior, e.g. such a temperature as will enable the inner parts of thehose to stand a strong transformation, especially a considerablestretching, but still a temperature which is essentially lower than theextruding temperature and lower than the temperature at which extrudingtakes place in the hitherto known bottle blowing methods with a directtransfer of the extruded material to the mold. In the heating apparatusespecially, the outer parts of the hoses are heated.

The machine functions in the way that as the table 4 with the open mold5, 6 is lifted, the mold is closed round a piece of hose hanging downfrom the heating apparatus, and a cutting is undertaken by means of theknife driven by the pressure means cylinder 61. Thereafter a blowing-upis undertaken of the hose piece present in the mold by means of theblowing nozzle 9 projecting vertically up into the mold, which blowingnozzle also forms the molding core for the bottle neck. At the sametime, the table 4 with the mold 5, 6 is lowered thus making room for thecontinued downward movement of the hose 54. When the bottle formed inthe mold 5, 6 by the blowing-up operation is stabilized, the mold isopened, and the bottle remove-d, whereafter the table is again lifted.This series of operations is adjusted to the speed of the movement ofthe hose in such a manner that after the lifting of the table the moldcan immediately close round a fresh piece of hose.

The illustrated and described embodiments and the methods describe-d inconnection herewith are only to be considered as examples seeing thatwithin the scope of the invention many variations are possible. Thus, itwill be possible, without any further arrangement, to let the hoseleaving the cooling apparatus 55 be transferred to storing coils thusworking up a store of hose, and such hose may later at a convenientmoment be passed through the heating apparatus 60 to the bottle blowingapparatus proper. It will, of course, also be possible to buy such hoseand let it pass the heating apparatus. When such stored articles areused it will probably be advantageous to let the hose pass acomparatively long heating apparatus before it is introduced into theheating apparatus which is meant to give the hose a short intensiveheating. In such a pre-heating, the hose may in its entire thickness beheated to a temperature in the vicinity of the plasticity boundary. Itwill also be possible to work with a band material of another profile,e.g. ribbon-shaped, in which case a welding together must be undertakenin the mold. Such a welding together may be rendered more easy byarranging the heating apparatus so that it is capable of giving thezones in question an esepcially strong heating. It is also possible toallow the hose to pass through the heating apparatus in steps. Where, asin FIG. 7, the hose is fed from an extruder, it will be prac tical inorder to obtain such a movement in steps between the extru-der and theheating apparatus to insert movable guiding rollers. For instance, therollers 58 and 59 might be vertically movable in time with the speed ofextruding so that for a certain time of the period they movecomparatively slowly upwards whereby the hose is kept still in theheating apparatus, and for another part of the period they are movedcomparatively quickly downwards. By this arrangement, it is obtainedthat it is not necessary to move the table 15 with the mold up and down,or to undertake any other movement of the mold in order to move it awayfrom the zone immediately under the heating apparatus 60. In such amovement in steps it will, moreover, be easy to undertake a heatingvaried according to the longitudinal direction of the hose so that anadaptation may be undertaken according to the molding and weldingconditions on the various places in the mold. It will also be possibleto effect the cutting of the hose at a time other than the one explainedin connection with FIG. 7. Thus, the hose may be cut before being fedinto the heating apparatus thereby rendering it possible to undertake aninner heating of the hose. Such cut hose pieces may be moved in thelateral direction up to the place in the heating apparatus from wherethey are to be transferred to the mold. By such cutting it will on thewhole be possible to obtain the advantage that the method and theapparatus can be varied considerably in many respects. On the otherhand, said cutting before the introduction into the heating apparatuscauses that special holding members for the hose pieces must be arrangedfor.

What is claimed is:

1. An apparatus for manufacturing hollow articles from thermoplasticmaterial work pieces by molding in sequence, which comprises at leastone mold having a pair of separable parts, means for opening said mold,a transport mechanism including an endless conveyor belt for carryingsaid thermoplastic work pieces through a heating device and to aposition directly adjacent said mold after emerging from said heatingdevice, members on said belt for engaging one end of each work piece andsuspending it from its top in a generally perpendicular orientationWhile carrying the work pieces one at a time in between the mold parts,means for closing the mold parts about said work pieces while they aresuspended from said conveyor belt, and means for blowing up a work pieceplaced in the closed mold.

2. The apparatus as claimed in claim 1, wherein means are provided formoving said mold between two positions, where in one position it isclosed around a work piece fed by the conveyor belt, means for movingsaid mold in closed condition to a second position, thereby vacating theinitial position of said mold.

3. The apparatus as claimed in claim 1, wherein the transport mechanismis arranged for stepwise feeding of the work pieces and for retainingeach work piece for a short time at the place where the mold is operatedto close around the work piece.

4. The apparatus as claimed in claim 11, wherein means are provided formoving the mold in vertical direction.

5. Apparatus for manufacturing hollow articles from thermoplasticmaterial in a molding machine which comprises in combination an endlessconveyor for feeding a plurality of pre-formed tubular pieces of saidmaterial for further shaping in sequence, means for holding said tubularpieces individually suspended from their top in vertical position fromsaid conveyor, means for heating said tubular pieces while they aresuspended from their top and fed toward a molding station, said conveyorincluding a portion passing directly adjacent the molding station andmeans for moving the molding station of said molding machine intosurrounding relationship about said tubular pieces while said piecesremain suspended from said con veyor.

6. Apparatus for manufacturing hollow articles from preformed parisonsat substantially ambient temperature made of thermoplastic materialcomprising, in combination, a molding machine having a molding station,an oven having an entry opening and a discharge opening for raising thetemperature of said parisons to molding temperature, and a conveyormechanism for transporting said preformed parisons through said oven tothe molding station of said molding machine; said conveyor mechanismincluding a plurality of individual and separably movable mandrelconveyor elements upon which at least one preformed parison may bemounted, means for guiding said mandrel conveyor elements in an endlesspathway passing through said oven, molding station and back to saidoven, and means for intermittently and periodically moving one of saidmandrel conveyor elements from the discharge opening of said oven intosaid molding station to thereby force the previously blow-molded parisonand its associated mandrel conveyor element from said molding stationalong said endless pathway toward the entry opening of said oven.

7. Apparatus according to claim 6 wherein each of said mandrel conveyorelements includes at least one cross-bar having means at opposite endsthereof for supporting a pair of parisons from their top in a pendantposition.

8. Apparatus in accordance with claim 6 wherein said guiding meansincludes a U shaped channel having grooves formed in the inner sidewalls thereof, said mandrel conveyor elements including bearing meanscooperative with and engaging said grooves to maintain and slidablymount said elements in said guiding means.

9. Apparatus in accordance with claim 7 wherein said oven includes apair of spaced internal partition walls and 1. 1 1 2 blower meanstherebetween and cooperative therewith to 3,079,631 3/ 1963 Gasmire 185X circulate heated air over and around said mandrel con- 3,079,6373/1963 Marzillier 185 X veyor elements and the parisons suspendedtherefrom. 36, 6/1965 Dobbins et a1 185 References Cited 5 26 FOREIGNPATENTS UNITED STATES PATENTS 1, 1,774 4/1961 France. 2 819,490 1/1958Froot 1 5 I. SPENCER OVERHOLSER, Primary Examiner.

2,978,745 4/1961 Langecker 185 X W. L. MCBAY, Assistant Examiner.

1. AN APPARATUS FOR MANUFACTURING HOLLOW ARTICLES FROM THERMOPLASTICMATERIAL WORK PIECES BY MOLDING IN SEQUENCE, WHICH COMPRISES AT LEASTONE MOLD HAVING A PAIR OF SEPARABLE PARTS, MEANS FOR OPENINGS SAID MOLD,A TRANSPORT MECHANISM INCLUDING AN ENDLESS CONVEYOR BELT FOR CARRYINGSAID THERMOPLASTIC WORK PIECES THROUGH A HEATING DEVICE AND TO APOSITION DIRECTLY ADJACENT SAID MOLD AFTER EMERGING FROM SAID HEATINGDEVICE, MEMBERS ON SAID BELT FOR ENGAGTING ONE END OF EACH WORK PEICEAND SUSPENDING